/*BEGIN_COPYRIGHT_BLOCK

*

* Copyright (c) 2001-2015, JavaPLT group at Rice University (drjava@rice.edu)

* All rights reserved.

*

* Redistribution and use in source and binary forms, with or without

* modification, are permitted provided that the following conditions are met:

* * Redistributions of source code must retain the above copyright

* notice, this list of conditions and the following disclaimer.

* * Redistributions in binary form must reproduce the above copyright

* notice, this list of conditions and the following disclaimer in the

* documentation and/or other materials provided with the distribution.

* * Neither the names of DrJava, DrScala, the JavaPLT group, Rice University, nor the

* names of its contributors may be used to endorse or promote products

* derived from this software without specific prior written permission.

*

* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR

* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*

* This software is Open Source Initiative approved Open Source Software.

* Open Source Initative Approved is a trademark of the Open Source Initiative.

*

* This file is part of DrScala. Download the current version of this project

* from http://www.drscala.org/.

*

* END_COPYRIGHT_BLOCK*/

package edu.rice.cs.drjava.ui;

import java.io.*;

import javax.swing.*;

import java.awt.event.*;

import java.awt.*;

import edu.rice.cs.util.swing.Utilities;

/** Panel for displaying some component with buttons, one of which is an "Abort" button.

* This should be used to display the output of an external process.

* This class is a swing class that should only be accessed from the event thread.

* @version $Id: LessPanel.java 5594 2012-06-21 11:23:40Z rcartwright $

*/

public class LessPanel extends AbortablePanel {

/** Size of the buffer read at once. */

public final int BUFFER_SIZE = 10240;

/** Number of buffer reads before the event thread is allowed to do something else. */

public final int BUFFER_READS_PER_TIMER = 5;

protected JTextArea _textArea;

protected File _f = null;

protected FileReader _fr = null;

protected JButton _updateNowButton;

protected JButton _restartButton;

protected Thread _updateThread;

private char[] _buf = new char[BUFFER_SIZE];

private int _red = -1;

private long _totalRead = 0;

/** Constructs a new "less" panel to watch file output.

* This is swing view class and hence should only be accessed from the event thread.

* @param frame the MainFrame

* @param title title of the pane

* @param f file to monitor

*/

public LessPanel(MainFrame frame, String title, File f) {

super(frame, title);

initThread(f);

updateText();

// MainFrame.LOG.log("\tLessPanel ctor done");

}

protected void initThread(File f) {

try {

// MainFrame.LOG.log("\tLessPanel ctor");

// MainFrame.LOG.log("\texists: " + f.exists());

// MainFrame.LOG.log("\tcanRead: " + f.canRead());

// MainFrame.LOG.log("\tisFile: " + f.isFile());

if (f.exists() && f.canRead() && f.isFile()) {

// MainFrame.LOG.log("\texists, can be read, is file");

// MainFrame.LOG.log("\tfile length = " + f.length());

_f = f;

_fr = new FileReader(_f);

_red = -1;

_totalRead = 0;

_updateThread = new Thread(new Runnable() {

public void run() {

while(_fr != null) {

try {

Thread.sleep(edu.rice.cs.drjava.DrScala.getConfig().

getSetting(edu.rice.cs.drjava.config.OptionConstants.FOLLOW_FILE_DELAY));

}

catch(InterruptedException ie) { /* ignore */ }

updateText();

}

}

});

_updateThread.start();

_updateNowButton.setEnabled(true);

// MainFrame.LOG.log("\tUpdate thread started");

}

}

catch(Exception e) {

_fr = null;

}

}

/** Setup left panel. Must be overridden to return the component on the left side. */

protected Component makeLeftPanel() {

_textArea = new JTextArea();

_textArea.setEditable(false);

return _textArea;

}

/** Abort action was performed. Must be overridden to return the component on the left side. */

protected void abortActionPerformed(ActionEvent e) {

if (_fr != null) {

try {

_fr.close();

}

catch(IOException ioe) { /* ignore, just stop polling */ }

_fr = null;

updateButtons();

}

}

/** Update button state and text. Should be overridden if additional buttons are added besides "Go To", "Remove" and "Remove All". */

protected void updateButtons() {

_abortButton.setEnabled(_fr != null);

_updateNowButton.setEnabled(_fr != null);

_restartButton.setEnabled(_fr == null);

}

/** Creates the buttons for controlling the regions. Should be overridden. */

protected JComponent[] makeButtons() {

_updateNowButton = new JButton("Update");

_updateNowButton.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) { updateText(); }

});

_restartButton = new JButton("Restart");

_restartButton.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) { restartFollowing(); }

});

_restartButton.setEnabled(false);

return new JComponent[] { _updateNowButton, _restartButton };

}

/** Restart following this file. */

protected void restartFollowing() {

_textArea.setText("");

initThread(_f);

updateText();

}

/** Update the text area if there is new text in the file.

* May not read all new text if there is too much, as that would

* block the event thread for too long. */

protected void updateText() {

Utilities.invokeLater(new Runnable() {

public void run() {

// MainFrame.LOG.log("updateText");

if ((_fr != null) &&

(_updateNowButton.isEnabled())) {

_updateNowButton.setEnabled(false);

int changeCount = 0;

long newSize = _f.length();

if (_totalRead!=newSize) {

if (_totalRead>newSize) {

// must start over, file got smaller!

_textArea.setText("");

_totalRead = 0;

}

StringBuilder sb = new StringBuilder(_textArea.getText());

// MainFrame.LOG.log("\tgot text");

try {

_fr.close();

_fr = new FileReader(_f);

_fr.skip(_totalRead);

// MainFrame.LOG.log("\treading... skipped to " + _totalRead);

// abort after reading 5 blocks (50 kB), read more later

// don't block the event thread any longer

while((changeCount<=BUFFER_READS_PER_TIMER) && ((_red = _fr.read(_buf)) >= 0)) {

// MainFrame.LOG.log("\tread " + _red + " bytes");

_totalRead += _red;

sb.append(new String(_buf, 0, _red));

++changeCount;

}

if ((_red > 0) && (changeCount<BUFFER_READS_PER_TIMER)) {

_totalRead += _red;

sb.append(new String(_buf, 0, _red));

++changeCount;

}

}

catch(IOException ioe) {

// MainFrame.LOG.log("\taborted");

// stop polling

sb.append("\n\nI/O Exception reading file " + _f + "\n");

++changeCount;

abortActionPerformed(null);

}

finally {

if (changeCount > 0) {

// MainFrame.LOG.log("\tsetting text");

_textArea.setText(sb.toString());

int maxLines = edu.rice.cs.drjava.DrScala.getConfig().

getSetting(edu.rice.cs.drjava.config.OptionConstants.FOLLOW_FILE_LINES);

if (maxLines > 0) { // if maxLines is 0, buffer is unlimited

try {

int start = 0;

int len = _textArea.getText().length();

int curLines = _textArea.getLineCount();

if (curLines>maxLines) {

start = _textArea.getLineStartOffset(curLines-maxLines);

len -= start;

sb = new StringBuilder(_textArea.getText(start,len));

_textArea.setText(sb.toString());

}

}

catch(javax.swing.text.BadLocationException e) { /* ignore, do not truncate */ }

}

// MainFrame.LOG.log("\ttext length = " + s.length());

}

}

}

}

// MainFrame.LOG.log("\tupdating buttons");

updateButtons();

}

});

}

}